The CHRNA3/5 SNPs were also associated with lung function (FEV1) in the ICGN and BEOCOPD populations. These SNPs were shown to be associated with FEV1 in the British Birth Cohort (rs8034191 and rs1051730, p = 0.029 and 0.023, respectively (http://www.b58cgene.sgul.ac.uk/, accessed [3/7/2008]). Historically, nicotinic receptors are classified as neuronal or muscle-type, based on their initial site of identification and composite subunits [17]. Cholinergic activity in the airways primarily induces tracheo-bronchial smooth muscle contraction and mucous secretion. However, there is an increasing body of literature showing the importance of extra-neuronal cholinergic signaling [18] in the lung.
